1. Field of the Invention
The invention relates to vehicle anti-theft entry system, and in particular, to vehicle anti-theft entry systems that are lower cost and somewhat less amenable to hacking.
2. Description of the Related Art
Vehicles, such as over-the-road trucks, are often operated in fleets. More than one individual may have access to a particular vehicle. Some individuals, such as the driver, may be authorized to drive the vehicle over a particular route, during a particular period of time, such as a shift, or within a particular zone or territory. Other individuals, such as shop or repair personnel, may have access to the vehicle that is limited to a particular range operation or a particular schedule of diagnostic operations or tests. Still other individuals, such as fleet owners or managers, may have relatively unfettered access to vehicles. Finally, people who lack authorization to operate fleet vehicles at all, such as thieves or hijackers, may have no rightful access to operate fleet vehicles.
Vehicles are often equipped with vehicle control modules. These control modules may take the form of computerized controls, such as engine or transmission controls. Some vehicles have anti-theft schemes whereby a prospective operator may is required to identify himself to the vehicle control module in order to gain access to the vehicle. The range of access an operator is given may depend on the identity of the operator. Often the port of point of access to the vehicle is a computer-like screen with a keyboard into which the prospective operator enters a personal identification number (PIN) or other user identification key.
Since the vehicle control module may possess significant computing power, different levels of access may be granted to various users based on their particular identity. The computer may also be equipped with user interfaces that make accessing the vehicle control module convenient and easy. Often, however, the computer capability of the vehicle control module inadvertently provides feed-back to an unauthorized user that may be used to gain entry to the vehicle. Such unauthorized users are analogous to “hackers” and may be able to understand and defeat the vehicles authorization system using information provided inadvertently or unknowingly by the vehicle authorization system itself. Furthermore, computer screens and feedback devices, although not very expensive, may still be reduced in cost. Since prices of mass-produced vehicles are under severe competitive pressure at all times, even a small cost reduction may be of significance in the marketplace.